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The traditional method assesses the impact of fractures on electronics by calculating test results for many samples, which ignores variation in manufacturing parameters between individuals and does not accurately reflect the actual state. This article proposes a fracture analysis method for multilayer ceramic capacitors (MLCC) by the phase field because of complex structures and diverse manufacturing parameters. This method is based on Griffith’s theory, and the phase field to calculate crack expansion and fracture effects on the electric potential of MLCC is obtained. Finally, MLCC of packages 0603, 1210, and 2220 are studied as numerical examples of applications for investigation. Calculated results are consistent with tests, which verifies the accuracy of this method. In addition, the mechanism of the MLCC fracture on its electrical characteristics is given, and the impact of solder height and the internal electrode number on the fracture are analyzed using this method.

The design optimization of a robust, low-cost, and high-quality permanent magnet actuator (PMA) that meets the requirements of industrial applications presents numerous challenges. In particular, uncertainties arising from fabrication, assembly, and degradation are omnipresent and can produce erratic or infeasible solutions, complicating the robust design optimization (RDO) for PMAs. State-of-art RDO approaches treat these uncertainties as fixed contribution margins while disregarding the changes in the contribution margin, manufacturing cost, and life-cycle quality loss resulting from variations in uncertainty range and time-variant degradation. To address these issues, we propose a heuristic RDO approach for the batch production of PMAs that considers the manufacturing cost, life-cycle quality loss, and adaptive iterative step size to address these issues. Firstly, a unified manufacturing cost model is innovated to assess the complex component morphologies. Subsequently, a life-cycle dynamic quality loss model considering the time-variant degradation is established by applying the modified quality loss function, which can effectively track the losses caused by fluctuations in life-cycle quality. Based on the manufacturing cost and life-cycle quality loss models, a heuristic RDO approach with an adaptive iterative step size model is proposed, which automatically assigns the maximum bound of uncertainties and reduces the quality variation without significantly increasing manufacturing cost. Finally, a case study on a latching rotary PMA is used to illustrate the effectiveness of the proposed approach through simulation and experiment. This method achieves a 35.8% increase in robustness for batch-produced PMAs along with a 100% reduction in life-cycle quality losses at only a marginal increase of 5.9% in manufacturing costs.

Accidents of launch vehicles, satellites, and missiles originating from remainder particles account for 6% of the causes in accident investigations. The problem of remainder particles seriously reduces the reliability of sealed electronic components in aerospace. Numerous cases have shown that remainder particles cannot be completely avoided due to process, environment, and other factors. As an important method for detecting remainder particles, the particle impact noise detection (PIND) method has become a standard testing tool in the aerospace field in China. However, there is still a lack of effective and feasible solutions to the problems of sensor sensitivity measurement and consistency evaluation, which are key and indispensable components of the closed-loop process of the PIND method. Through numerous experiments, this article proposed a complete set of new methods and systems for the sensitivity measurement of PIND sensors, allowing real-time measurement of PIND sensor sensitivity at the production site without moving or disassembling the sensor. This article systematically illustrated the feasibility of this new method and system from the perspective of measurement method, measurement system, measurement result verification, and measurement system application. The accuracy and feasibility of the proposed method were verified using the free-field underwater comparison method. The average difference between the two methods was less than 1 dB (1 V/ $\mu $ bar), which meets the practical requirements (±3 dB). In addition, the coupling effect of different coupling agents, the full contact time of coupling agents, and the epoxy adhesive bonding process were further analyzed based on the proposed method and system, and satisfactory improvement results were obtained.

The bypass switch is a significant component of power electronic device protection. In case of a short circuit fault in the flexible dc transmission system, due to the rising rapidly fault current, the bypass switch must complete its closing operation quickly in 5 ms or even less. This puts forward strict requirements on the motion speed of the contacts. However, the high-speed closing leads to bounce which causes bypass failure. To address this problem, a high-speed soft-landing mechanism (SLM) based on electromagnetic repulsion force is proposed in this article. Compared with the traditional solenoid electromagnetic mechanism, the SLM can finish the closing motion in 3 ms, and the closing speed is 0.68 m/s, only about 1/4 of the traditional solenoid mechanism. Subsequently, the influence of the repulsion disk size and the buffer initiating time on the closing time and closing speed is further investigated. To achieve better dynamic characteristics, the inner radius of the repulsion disk should be smaller, and the outer radius should be greater than that of the coil. The optimal thickness of the repulsion disk and the buffer initiating time can be obtained through simulation analysis. The SLM solves the contradiction between the short closing time and the low closing speed of the bypass switch. It improves the reliability of power electronic device protection in the flexible dc transmission system, which is conducive to the system’s safe operation.